<!-- Licensed under a BSD license. See license.html for license -->
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=yes">
    <title>Three.js - Game - Just Player</title>
    <style>
    html {
      box-sizing: border-box;
    }
    *, *:before, *:after {
      box-sizing: inherit;
    }
    html, body {
        margin: 0;
        height: 100%;
    }
    #c {
        width: 100%;
        height: 100%;
        display: block;
    }
    #loading {
      position: absolute;
      left: 0;
      top: 0;
      width: 100%;
      height: 100%;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: center;
      font-size: xx-large;
      font-family: sans-serif;
        }
    #loading>div>div {
      padding: 2px;
    }
    .progress {
      width: 50vw;
      border: 1px solid black;
    }
    #progressbar {
      width: 0%;
      transition: width ease-out .5s;
      height: 1em;
      background-color: #888;
      background-image: linear-gradient(
        -45deg,
        rgba(255, 255, 255, .5) 25%,
        transparent 25%,
        transparent 50%,
        rgba(255, 255, 255, .5) 50%,
        rgba(255, 255, 255, .5) 75%,
        transparent 75%,
        transparent
      );
      background-size: 50px 50px;
      animation: progressanim 2s linear infinite;
    }

    @keyframes progressanim {
      0% {
        background-position: 50px 50px;
      }
      100% {
        background-position: 0 0;
      }
    }
  </style>
  </head>
  <body>
    <canvas id="c"></canvas>
    <div id="loading">
      <div>
        <div>...loading...</div>
        <div class="progress"><div id="progressbar"></div></div>
      </div>
    </div>
  </body>
<!-- Import maps polyfill -->
<!-- Remove this when import maps will be widely supported -->
<script async src="https://unpkg.com/es-module-shims@1.3.6/dist/es-module-shims.js"></script>

<script type="importmap">
{
  "imports": {
    "three": "../../build/three.module.js",
    "three/addons/": "../../examples/jsm/"
  }
}
</script>

<script type="module">
import * as THREE from 'three';
import {OrbitControls} from 'three/addons/controls/OrbitControls.js';
import {GLTFLoader} from 'three/addons/loaders/GLTFLoader.js';
import * as SkeletonUtils from 'three/addons/utils/SkeletonUtils.js';

function main() {
  const canvas = document.querySelector('#c');
  const renderer = new THREE.WebGLRenderer({canvas});
  renderer.outputEncoding = THREE.sRGBEncoding;

  const fov = 45;
  const aspect = 2;  // the canvas default
  const near = 0.1;
  const far = 1000;
  const camera = new THREE.PerspectiveCamera(fov, aspect, near, far);
  camera.position.set(0, 40, 80);

  const controls = new OrbitControls(camera, canvas);
  controls.target.set(0, 5, 0);
  controls.update();

  const scene = new THREE.Scene();
  scene.background = new THREE.Color('white');

  function addLight(...pos) {
    const color = 0xFFFFFF;
    const intensity = 0.8;
    const light = new THREE.DirectionalLight(color, intensity);
    light.position.set(...pos);
    scene.add(light);
    scene.add(light.target);
  }
  addLight(5, 5, 2);
  addLight(-5, 5, 5);

  const manager = new THREE.LoadingManager();
  manager.onLoad = init;

  const progressbarElem = document.querySelector('#progressbar');
  manager.onProgress = (url, itemsLoaded, itemsTotal) => {
    progressbarElem.style.width = `${itemsLoaded / itemsTotal * 100 | 0}%`;
  };

  const models = {
    pig:    { url: 'resources/models/animals/Pig.gltf' },
    cow:    { url: 'resources/models/animals/Cow.gltf' },
    llama:  { url: 'resources/models/animals/Llama.gltf' },
    pug:    { url: 'resources/models/animals/Pug.gltf' },
    sheep:  { url: 'resources/models/animals/Sheep.gltf' },
    zebra:  { url: 'resources/models/animals/Zebra.gltf' },
    horse:  { url: 'resources/models/animals/Horse.gltf' },
    knight: { url: 'resources/models/knight/KnightCharacter.gltf' },
  };
  {
    const gltfLoader = new GLTFLoader(manager);
    for (const model of Object.values(models)) {
      gltfLoader.load(model.url, (gltf) => {
        model.gltf = gltf;
      });
    }
  }

  function prepModelsAndAnimations() {
    Object.values(models).forEach(model => {
      const animsByName = {};
      model.gltf.animations.forEach((clip) => {
        animsByName[clip.name] = clip;
        // Should really fix this in .blend file
        if (clip.name === 'Walk') {
          clip.duration /= 2;
        }
      });
      model.animations = animsByName;
    });
  }

  function removeArrayElement(array, element) {
    const ndx = array.indexOf(element);
    if (ndx >= 0) {
      array.splice(ndx, 1);
    }
  }

  class SafeArray {
    constructor() {
      this.array = [];
      this.addQueue = [];
      this.removeQueue = new Set();
    }
    get isEmpty() {
      return this.addQueue.length + this.array.length > 0;
    }
    add(element) {
      this.addQueue.push(element);
    }
    remove(element) {
      this.removeQueue.add(element);
    }
    forEach(fn) {
      this._addQueued();
      this._removeQueued();
      for (const element of this.array) {
        if (this.removeQueue.has(element)) {
          continue;
        }
        fn(element);
      }
      this._removeQueued();
    }
    _addQueued() {
      if (this.addQueue.length) {
        this.array.splice(this.array.length, 0, ...this.addQueue);
        this.addQueue = [];
      }
    }
    _removeQueued() {
      if (this.removeQueue.size) {
        this.array = this.array.filter(element => !this.removeQueue.has(element));
        this.removeQueue.clear();
      }
    }
  }

  class GameObjectManager {
    constructor() {
      this.gameObjects = new SafeArray();
    }
    createGameObject(parent, name) {
      const gameObject = new GameObject(parent, name);
      this.gameObjects.add(gameObject);
      return gameObject;
    }
    removeGameObject(gameObject) {
      this.gameObjects.remove(gameObject);
    }
    update() {
      this.gameObjects.forEach(gameObject => gameObject.update());
    }
  }

  const globals = {
    time: 0,
    deltaTime: 0,
  };
  const gameObjectManager = new GameObjectManager();

  class GameObject {
    constructor(parent, name) {
      this.name = name;
      this.components = [];
      this.transform = new THREE.Object3D();
      parent.add(this.transform);
    }
    addComponent(ComponentType, ...args) {
      const component = new ComponentType(this, ...args);
      this.components.push(component);
      return component;
    }
    removeComponent(component) {
      removeArrayElement(this.components, component);
    }
    getComponent(ComponentType) {
      return this.components.find(c => c instanceof ComponentType);
    }
    update() {
      for (const component of this.components) {
        component.update();
      }
    }
  }

  // Base for all components
  class Component {
    constructor(gameObject) {
      this.gameObject = gameObject;
    }
    update() {
    }
  }

  class SkinInstance extends Component {
    constructor(gameObject, model) {
      super(gameObject);
      this.model = model;
      this.animRoot = SkeletonUtils.clone(this.model.gltf.scene);
      this.mixer = new THREE.AnimationMixer(this.animRoot);
      gameObject.transform.add(this.animRoot);
      this.actions = {};
    }
    setAnimation(animName) {
      const clip = this.model.animations[animName];
      // turn off all current actions
      for (const action of Object.values(this.actions)) {
        action.enabled = false;
      }
      // get or create existing action for clip
      const action = this.mixer.clipAction(clip);
      action.enabled = true;
      action.reset();
      action.play();
      this.actions[animName] = action;
    }
    update() {
      this.mixer.update(globals.deltaTime);
    }
  }

  class Player extends Component {
    constructor(gameObject) {
      super(gameObject);
      const model = models.knight;
      this.skinInstance = gameObject.addComponent(SkinInstance, model);
      this.skinInstance.setAnimation('Run');
    }
  }

  function init() {
    // hide the loading bar
    const loadingElem = document.querySelector('#loading');
    loadingElem.style.display = 'none';

    prepModelsAndAnimations();

    {
      const gameObject = gameObjectManager.createGameObject(scene, 'player');
      gameObject.addComponent(Player);
    }
  }

  function resizeRendererToDisplaySize(renderer) {
    const canvas = renderer.domElement;
    const width = canvas.clientWidth;
    const height = canvas.clientHeight;
    const needResize = canvas.width !== width || canvas.height !== height;
    if (needResize) {
      renderer.setSize(width, height, false);
    }
    return needResize;
  }

  let then = 0;
  function render(now) {
    // convert to seconds
    globals.time = now * 0.001;
    // make sure delta time isn't too big.
    globals.deltaTime = Math.min(globals.time - then, 1 / 20);
    then = globals.time;

    if (resizeRendererToDisplaySize(renderer)) {
      const canvas = renderer.domElement;
      camera.aspect = canvas.clientWidth / canvas.clientHeight;
      camera.updateProjectionMatrix();
    }

    gameObjectManager.update();

    renderer.render(scene, camera);

    requestAnimationFrame(render);
  }

  requestAnimationFrame(render);
}

main();
</script>
</html>
